1. Field of the Invention
This invention relates generally to the rinsing or cleaning of surface-treated articles or workpieces, and more particularly to an environmental waste-control apparatus and process for counterflow spray rinsing of chemically treated, anodized, plated or otherwise processed workpieces, utilizing a single on-line rinse tank or station with successively less contaminated rinsing solutions that are stored in a plurality of off-line tanks.
2. Description of the Prior Art
As is well known in the art, various problems and difficulties are encountered in providing suitable and efficient water-rinsing means for rinsing or cleaning of chemically treated articles or workpieces. Rinsing of a workpiece is generally required after it has been chemically or similarly treated by one of several processes whereby the workpiece or article is cleaned to prevent staining or to prevent the contamination of any sequential processes that might be necessary. This rinsing is generally done by placing the treated parts in a tank of running water or rinse solution, or sequentially dipping the parts in several tanks. However, sprays using water-rinsing solutions have been utilized for a rinsing method wherein several rinse stations are sequentially employed. Sprays have also been utilized in combination with flooded rinse tanks.
The combination of rinsing, using both the flooded tanks and sprays, is advocated by H. L. Pinkerton and A. Kenneth Graham, in their chapter on rinsing in "Electroplating Engineering Handbook", third edition, edited by A. Kenneth Graham, 1971 (Library of Congress Catalog Card No. 75-12904), where they stated:
"Water Economy PA1 Where space is limited, tank and spray combinations offer many advantages. Indeed they offer advantages even where space is not limited. These combinations are excellent with most rack rinsing. They are not of much value in barrel rinsing. PA1 The particular advantage of combining a spray with a tank is this: the spray can tremendously increase the rinsing efficiency as it may provide the equivalent of one or more additional rinse tanks! Consider the arrangement shown in FIG. (68). It is a single rinse tank with a double spray. The work leaving the plating is sprayed over the plating tank by the water exiting from the rinse tank. Now the work goes into the rinse tank for a soak rinse, then as it is lifted out it gets sprayed by the incoming clean water feed to the rinse tank. The sprays are activated only when work leaves the tanks."
Several means for achieving economy of water have already been mentioned: PA2 (1) Multiple countercurrent rinsing. PA2 (2) Spray rinsing. PA2 (3) Spray-and-dip rinsing. PA2 Additional water may be saved if sprays are fed by water pumped from a succeeding rinse tank."
Further, Joseph B. and Arthur S. Kushner state in their book "Water and Waste Control for the Plating Shop", dated 1972, on page 213: